Inline audio/visual conversion

ABSTRACT

A system, method, and apparatus for inline audio/visual conversion are described. Power to an inline converter is provided over the A/V cable that couples the converter to a destination such as a selector.

PRIORITY TO PROVISIONAL APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/793,831, filed Apr. 21, 2006.

FIELD OF INVENTION

The field of invention relates generally to the audio/visual (A/V)hardware, and, more specifically, to a converting analog or digital A/Vstreams into a single digital signal such as a High-DefinitionMultimedia Interface (HDMI) signal, converting a single digital signalinto analog or digital A/V streams, and switching between multipledigital signals.

BACKGROUND

As digital displays such High-Definition Television (HDTV), DigitalTelevision (DTV), and high resolution computer displays are becomingmore common place, HDMI connections have become the desired way to bringA/V streams into digital displays as a HDMI cable carries both digitalvideo and digital audio on a single cable.

However, most end-users will not also update all of their non-HDMIcompatible legacy A/V devices (such as a set top box, video gameconsole(s), VCR, DVR, DVD player, etc.). Rather, these users may need orwant to convert the outputs from these devices from older analoginterfaces, including composite, component, S-video, VGA, etc., to thenewer HDMI standard. Even when the digital display supports the olderinterfaces, the physical nature of the device (e.g., flat panel mountedon a wall) may not make it easy or attractive to have multiple cableshanging from the display. Additionally, having multiple cables in closeproximity can lead to the bleeding of signals from one cable to anothercausing interference in either the picture or audio.

FIG. 1 illustrates an exemplary prior art analog-to-DVI converter 101.This converter 101 takes an analog video input 105 (VGA or component)and converts that analog input into a Digital Visual Interface (DVI)output 107. Unfortunately, like all converters of this nature, converter101 requires a direct external socket power source to supply theconverter 101 with the power necessary to drive its conversion circuitrythrough port 103. For example, the converter 101 may use a transformerplugged into a wall socket to provide DC voltage to it or include atransformer inside of the converter's shell that is supplied an ACvoltage from a wall socket.

FIG. 2 illustrates an exemplary prior art HDMI switch 201. Thisparticular switch takes in two HDMI inputs 203, 205 and has one HDMIoutput 207 that is selected from one of the two inputs. Like the priorart converters, prior art HDMI switches require a direct external powersource to provide power to a port 209 of the switch 201.

FIG. 3 illustrates an exemplary prior art A/V receiver 301. Thisreceiver 301 takes in multiple traditional A/V sources 303_1 and 303_2,multiple HDMI sources 303_3 and 303_4, and outputs a single HDMI output307. A/V receivers with HDMI pass-through also have their drawbacks.Like the prior art converters and switches, prior art A/V receiversrequire a direct external power source to provide power to a port 305.A/V receivers are also bulky and expensive when compared to a simpleswitch or converter. While A/V receivers also likely have features thatare never used and not enough of the features (inputs) that a userwants, the user is saddled with the capabilities of the A/V receiverthat is neither flexible or “future proof.”

BREIF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and notlimitation, in the figures of the accompanying drawings in which likereferences indicate similar elements and in which:

FIG. 1 illustrates an exemplary prior art analog to DVI converter;

FIG. 2 illustrates an exemplary prior art HDMI switch;

FIG. 3 illustrates an exemplary prior art A/V receiver;

FIG. 4 illustrates an example of using a selector and one or moreconverters to provide a single digital A/V stream from multiple inputsignals to a destination;

FIG. 5 illustrates an embodiment of circuitry of an inline sourceconverter;

FIG. 6 illustrates an embodiment of a selector that provides power to aconverter;

FIG. 7 illustrates an embodiment of two HDMI connectors used as a sinkand a source connector;

FIG. 8 is an embodiment of a method of providing and maintaining powerfrom a selector to source converter over a cable;

FIG. 9 is an embodiment of a method of a converter receiving andmaintaining power from a selector;

FIG. 10 illustrates an embodiment of a digital A/V stream converter;

FIG. 11 is an embodiment of a method of providing and maintaining powerfrom a selector to a digital A/V stream converter;

FIG. 12 is an embodiment of a method of a digital A/V stream converterreceiving and maintaining power from a selector;

FIG. 13 illustrates an embodiment of an extended HDMI interface;

FIG. 14 illustrates an embodiment of the external connections of an HDMIswitch that utilizes an extended HDMI interface; and

FIG. 15 shows an embodiment of a computing system.

SUMMARY

A system, method, and apparatus for inline audio/visual conversion aredescribed. Power to an inline converter is provided over the A/V cablethat couples the converter to a destination such as a selector.

DETAILED DESCRIPTION

As described earlier, the prior art approaches to HDMI switch and analogto HDMI conversion all have their drawbacks and failings. For example,HDMI switches do not provide the flexibility to use any type ofconnection that a user has and HDMI converters require external power toconvert analog signals or switch sources. An improved approach allowsusers to connect a number of older and newer format devices to a singledevice with a selectable output to the digital display. The approachshould be flexible enough to support today's different inputcombinations and easily upgrade older devices or add new devices in thefuture.

Modular Conversion

FIG. 4 illustrates an example of using a selector and one or moreconverters to provide a single digital A/V stream from multiple inputsignals to a destination. In this example, there is a need to connectseveral different A/V devices 401, 402 to a single destination 407.These A/V source devices 401 may output any combination of analog videosignals (such as composite, component, S-video, etc.), analog audiosignals (left and right channel audio), digital video signals (such asDVI), and/or digital audio (optical or digital).

While one of these devices 402 is in the format that the selector 405accepts, two of these devices require an inline source converter 403 toconvert their outputs (analog or digital) into a digital format that isacceptable to the selector. For example, these outputs may be convertedinto a single digital A/V stream instead of the multiple signals thatare typically associated with these devices. In an embodiment, theseanalog or digital outputs are converted into the HDMI format which is asingle digital A/V stream.

An N×M HDMI selector 405 receives up to N A/V outputs from these A/Vdevices 401, 402 and outputs M single digital A/V streams (N and M maybe any number 1 or greater). The use of the inline converters 403injunction with the selector 405 allows for a more flexible approachthan the traditional receiver or switch provides as all that is neededto connect a new device that cannot be accepted by the selector 405 isthe appropriate converter cable 403. Because of this, a user is not tiedto some set of pre-chosen selector inputs that may not fulfill his/herneeds. The destination 407 may be anything that accepts single digitalA/V stream as a source including a digital display such as an HDTV, DLPproject, etc. or a conversion cable.

In an effort to help make the following description easier to followsome terms are herein defined. The output from an inline converter cablecomes from an “inline converter source port.” This output is so namedbecause it will be the source to an input of the selector 405. Theselector 405 has N inputs that are called “selector sink ports” whichreceive data from the output the inline converter cables. The selector405 also has M outputs called “selector source ports” which provide aninput for destination 407. Finally, destination 407 has an inlineconverter sink port that receives a single digital A/V stream from theselector's 405 selector source port. For example, converter 1 403_1 mayoutput an HDMI signal from its inline converter source port which iscoupled to a selector sink port of selector 405 and selector 405 mayoutput an HDMI signal from one of its selector source port's to aninline converter sink port of destination 407.

Conversion Circuitry

Traditionally, single digital A/V stream cables, such as HDMI cables,have been used almost exclusively for transmitting A/V data and notreceiving data or power (one exception being that pin 19 of a Type AHDMI connection is used for “hot plug” detection). For this reason, allof the prior art approaches to analog-to-DVI or HDMI conversion requireda power source external to the conversion circuitry to power theconversion circuitry. This extra power source is often a cumbersomeapparatus and limits the flexibility where these converters are usable.

FIG. 5 illustrates an embodiment of circuitry of an inline sourceconverter. This converter 403 converts one or more analog and/or digitalvideo and/or audio source signals into a single digital A/V stream suchas HDMI. An input video connector 515 receives one or more videosignals. These signals are passed to a video decoder circuit 503 toconvert analog or digital video of different formats (SDTV, HDTV, NTCS,PAL, etc) and standards (RGB, SCART, Composite, Component, S-Video, DVI,SDI, etc.) into digital signals of different color space (RGB, YCrCb,etc). Outputs from the video decoder 503 include a group of digitalsignals composed of 24 to 36 digital signals to support different colorresolutions (8, 10 or 12 bits per color, either 4:2:2 or 4:4:4) andcolor spaces (RGB or YCrCb). The video decoder 503 may support severaldifferent analog and/or digital video standards or be specific to justone video standard. For example, the video decoder 503 may support oneor more of the following analog video standards: Composite (CVBS),Component (Pb, Pr, and Y), S-Video (Y and C), and RGB (R, G, B, Hs, &Vs); and digital video standards such as DVI. The converted digitalvideo signals are transmitted to either the optional video data mappingcircuit 507 or to the encoder 511 depending upon the configuration ofthe inline converter.

This circuit 503 also extracts timing information, embedded in the videostream, into dedicated output signals which are transmitted to thecoupled encoder circuit 511. Exemplary timing information includes, butis not limited to, horizontal and vertical syncs, data enable (turn on)information, and pixel clock information. Exemplary circuits that may beused for the video decoder circuit 503 include, but not limited to,Analog Devices' ADV7403 and Philips' SAV7118.

An audio connector 517 receives one or more analog or digital inputsdepending upon which type of connector (analog or digital) is used.These inputs are passed at audio receiver 505. If an analog audio inputis received, the audio receiver 505 converts source analog audio signalsinto a serial digital stream including serial audio data, clock, andleft/right channel select. For example, the audio receiver 505 mayconvert left and right audio channels into Inter-IC Sound (I2S) signalsof different sampling rates. This digital stream is transmitted to theencoder circuit 511. Exemplary circuits that may be utilized as theaudio ADC 505 include, but are not limited to, Asahi Kasei's AK5357.

If the audio stream is digital, then this circuit 505 may be an opticalor non-optical receiver to support digital audio in the form of AES-EBUor Sony/Philips Digital Interface Format (SPDIF). Exemplary circuitsthat may be utilized as the receiver 505 include, but are not limitedto, Toshiba's TORX141.

The encoder circuit 511 is a specialized device that receives video dataoutput from the video decoder circuit 503 (and optional video datamapping circuit 507) and audio data from audio receiver 505 and convertsthem from separate (parallel) streams into an encoded single digitalserial A/V stream using timing signals from the video decoder circuit503.

In an embodiment, the single digital serial ANV stream is an HDMI streamand the encoder circuit 511 outputs two signal buses to the connector513. The first signal bus is the “TMDS” bus which is a group of fourpairs of signals containing the high-speed serial data. The secondsignal bus is the “DDC” bus which is a group of two signals used tosupport configuration and content protection.

Exemplary circuits that may be utilized as the encoder circuit 511 areSilicon Image's Sil9134 & Sil9030, and Analog Devices' AD9889.

The microcontroller or processor (MCU) 509 is a general purposecontroller that performs one or more of the following functions:configures the other circuits; maintains validation of communicationsover a reserved pin or pins of the cable carrying the single digital A/Vstream from the converter; software upgrades; monitor conversionactivities being performed; inspect signals; serially communicates witha connected device, etc. The MCU 509 provides and receives numerouscontrol signals to the other circuits. For example, the MCU 509 receivesinterrupts from the video decoder 503, audio receiver 505, and encoder511.

The MCU 509 provides the video decoder 503 with control signals that arein the form of a low-rate serial interface, such as I2C(Inter-Integrated Circuit) or SPI (Serial Peripheral Interface). Othercontrol signals provided to the video decoder 503 include signals forreset, interrupts, and select(s). Control signals to the audio receiver505 from the MCU 509 range from discrete signals to a serial bus in theform of I2C or SPI and may include reset, interrupts, and selectsignals. Exemplary circuits that may be utilized as the MCU 509 include,but not limited to, are Atmel's AT91SAM7S, Microchip's PIC18F8722, andOKI's ML67Q4061.

A source connector port 513 provides an interface for communicating withanother device such as a selector. The single digital A/V streamgenerated by the encoder circuit 511 is transmitted through thisconnector port 513 over a single cable to another device such as aselector.

The conversion circuitry also includes power circuitry 519. The powercircuitry receives power (current and voltage) through the singledigital A/V cable from an external device such as a selector andsupplies power to the other conversion circuits 503, 505, 507, 509, and511. Of course not every circuit has the same power requirements sovoltage dividers, etc. may need to be utilized to provide each circuitwith the proper power requirement. No prior art conversion system hasits conversion circuitry powered in this manner—each requires a directconnection to an external power source. For example, if the conversioncircuitry is creating and outputting an HDMI stream, pin 18 of a Type AHDMI connector carries power (+5V and approximately 50 mA or 500 mAcurrent) that is used to power circuitry 519 of the inline converterthrough a coupled HDMI cable from an external device. In other words,the external device provides power to the converter over the cable andeliminates the need for the converter to have a direct external powersource. Additionally, pin 14 of the HDMI connector (which is normallyreserved) is used to communicate information from the MCU 509 to anoutside device over the HDMI cable.

In an embodiment, the conversion circuitry includes a video data mappingcircuit 507 that is an active switch that arranges the bit ordering fromthe digital bus output of the video decoder 503 into the proper formatfor the encoder circuit 511. This ordering is performed to satisfyspecific requirements of different video formats and resolutions. There-ordering may only apply to a group of bits or the entire bus of bitstransmitted from the video decoder 503 to the video data mapping circuit507. Any active analog switch, such as the On Semi MC14016 orequivalent, is suitable for the application. The control signalsprovided to the video data mapping circuit 507 depend on the specificimplementation of the analog switch and could range from discretesignals to a serial bus in the form of I2C or SPI.

In some embodiments, inputs to the conversion circuitry are dedicatedA/V cables that are hardwired through the housing and not simplyports/connectors. In other embodiments, only the cables or ports for aparticular input are present. Similarly, the output may be a hardwiredcable (such as an HDMI cable or variant).

Selector

FIG. 6 illustrates an embodiment of a selector that provides power to aconverter. The selector includes N sink connectors 601_1 to 601_N. Onlyone cable may connect to a sink connector 601 at a time. Through theexisting power pin or pins of a sink connector 601 power (current andvoltage) may be supplied to a source device such as converter 403.Additionally, communications between the source device (converter 403)and selector may be transmitted through one or more reserved pins of thesink connector 601.

In an embodiment, the selector is an HDMI selector and accepts multipleHDMI inputs and outputs HDMI streams. If the standard 19-pin Type A HDMIconnector is used, pin 18 of each HDMI sink connector 601 is used tosense if a “normal” HDMI cable is connected to the selector through thesource connector 601 or if the cable that is attached is coupled to adevice that requires power. If the voltage on pin 18 is +5V, then it isassumed that a normal HDMI cable is connected and no power needs to besupplied. If the cable is coupled to a device that requires power suchas the converter described earlier then no voltage will be on pin 18.Pin 14 of the HDMI connector (which is normally reserved) is used tocommunicate information between the MCU 509 of the converter and the MCU605 of the selector.

A N×M switch 603 is used to switch between the N sources so that Moutputs are selected at a time. Typically, M is equal to 1 and N isgreater than 1. An output of the switch 603 is supplied to a sourceconnector port 607.

In an embodiment, the source connector port 607 is a standard HDMIconnector. Pins 18 and 14 of the HDMI source connector port 607 are usedin similar manner as pins 18 and 14 of the HDMI sink connectors 601. Theoutput of the source connector port 607 may be sent to a digitaldisplay, other selector, or to a digital converter. If the N×M switch603 is an HDMI switch, then exemplary circuits that may be utilized asthe switch 603 include, but not limited to, TI's TMDS341 and Pericom'sPI3HDMI341ART.

The MCU 605 is a general purpose controller that performs one or more ofthe following functions: configures the other circuits; maintainscommunications over attached cables with an inline converter thatrequires power from the selector; and software upgrades. The MCU 605provides and receives numerous control signals to the other circuits.The MCU 605 provides the N×1 HDMI switch 603 with a signal to selectwhich of the N inputs to output and a transmit enable (turn on) signal.

Additionally, one or more of the power circuits 609 provide a voltageand a current to one or more inline converters that require power(connections not shown). In one embodiment, the MCU 605 only providesthis voltage and current to sink connectors 601 or source connectors 607that have a converter coupled to them through a cable.

In an HDMI specific embodiment, a +5V reference and high- or low-currentare supplied to pin 18 of HDMI sink connector ports 601 and/or sourceconnector port 607. The circuitry of the HDMI selector may be power byan external power source.

FIG. 7 illustrates an embodiment of two HDMI connectors used as a sinkand a source connector. Both connectors have the Type A standard 19pins. Pin 18 711, 705 is used to transfer high-current and low-current+5V references from the selector to a converter. Pin 14 709, 707 is usedto transmit messages between the selector and converter.

Power from Selector to Source Converter

One or more of the circuits of the source conversion circuitry isprovided power (current and voltage) through the cable that is connectedto the selector. FIG. 8 is an embodiment of a method of providing andmaintaining power from a selector to source converter over a cable.

The selector 405 measures the voltage found on one or more of the sinkconnector power pins 601 at 801. For example, if using HDMI, the MCU 605of the selector 405 measures the voltage on pin 18 of one or more of thesink connector ports 601.

If there is a voltage present, then it is assumed that the coupleddevice does not need power. For example, if a standard HDMI sourcedevice is connected to the port it would not require power. The port isidentified as having a device that does not require power at 803.

If there is not a voltage present, a low-current reference voltage isprovided on one or more of the power pins by the power circuit 609selector 405 at 805. Typically, this low-current voltage is provided onthe behest of the MCU 605. This low-current reference voltage will becarried by the cable coupling the selector 405 and converter 403. Forexample, if using HDMI, a low-current +5V reference will be applied topin 18 of the sink connector port 601 and carried to pin 18 of theconverter 403. According to an embodiment, the current is on the orderof 50 mA.

Once a low-current voltage has been provided to the converter 403, acommunications link should be established between the selector 405 andconverter 403. This communication may be used to determine if theconverter 403 needs more current and if it is still alive. In anembodiment, the low-current voltage allows for at least a part of theMCU 509 of the converter 403 to be turned on and generate one or moremessages. In an embodiment, the converter 403 transmits a “presence”message over a reserved or unused pin of its connector port 513.

If a message has not been received at 807, then the low-currentreference voltage is removed from the power pin(s) at 809. This removalserves two purposes. First, it saves power by not unnecessarilyproviding power to a device (or no device) that does not need or wantthe power. Second, it will not provide a false positive if or when theselector measures the voltage on the pin(s) at some later point in time.

If a message is received at 807, the selector determines if the receivedmessage is a valid presence message at 811. For example, MCU 605executes a software routine to determine if the message received isvalid. If HDMI is being utilized, all messages are received ortransmitted on pin 14 of the respective HDMI connectors.

If the message is not valid, the low-current reference voltage isremoved from the power pin of the appropriate connectors 601. Forexample, the MCU 605 orders the power circuit 609 to stop providing thelow-current reference to the appropriate sink connector 601.

If the message is valid, then appropriate power pin(s) is supplied witha high-current reference voltage. For example, if HDMI is being used, ahigh-current of around 500 mA is supplied with a +5V reference. Thishigh-current reference allows the rest conversion circuitry of theconverter 403 to be activated.

Of course it should be understood that it is not overly important whichdevice initiates the establishment of a communications between thedevices. In an alternative embodiment, the selector 405 pings theconverter with a presence message after it has provided low-currentpower to the converter 403.

Because the converter 403 may be removed or stop functioning at a laterpoint in time, periodic presence checks are performed. The selector 405transmits a presence check message to the converter 403 at 815 and waitsfor a response message. If the selector 405 does not receive a responsemessage at 817, one of two actions may be taken depending upon theconfiguration of the selector 405. Another presence check message may betransmitted at 819 or the voltage for the power pin may be removed. Forexample, if only one presence message was sent, it may be that theconverter is too busy to respond and should be given another chance torespond as removing the high-current voltage reference would shut offthe conversion circuitry thereby causing an interruption in the singledigital A/V stream. Of course, it should be again understood that theconverter 403 could also initiate the presence check.

FIG. 9 is an embodiment of a method of a converter receiving andmaintaining power from a selector. The converter 403 receives alow-current reference voltage over a cable from the selector 405 at 901.For example, a +5V reference voltage is applied to pin 18 if HDMI isused.

The converter 403 transmits a presence message over one or more reservedor unused pins to the selector at 903. This is done over pin 14 if aType A HDMI connector is used. For example, once the MCU 509 is turnedon the by the low-current reference voltage, it prepares and transmits apresence message through pin 14 of the connector 513.

If the converter 403 receives a high-current reference voltage at 905 itmay transmit an acknowledgment message (depending upon the communicationconfiguration). The converter 403 enable (turn on) the remainingconversion circuits using the high-current reference voltage at 913. Ifthe converter 403 does not receive a high-current reference voltage at905, one or more of its conversion circuits will remain disabled at 907.

Periodically, the selector 405 may check to see if the converter 403 isstill alive and will transmit a presence check message to the converter403. If the converter 403 receives the presence check message at 909 itwill transmit a response message at 911 and awaits the next presencecheck message. Of course, it should be understood that the converter 403could also initiate the presence check and receive a response from theselector 405.

Power from Selector to Destination Converter

FIG. 10 illustrates an embodiment of a digital A/V stream converter. Asdescribed with respect to FIG. 4, a digital A/V stream converter 407 maybe the destination of a selector 405 instead of a display. The circuitryof this converter 407 receives a single digital A/V stream (such as anHDMI stream) and converts it into separate analog video and audiostreams, separate analog video and digital audio, separate digital videoand analog audio, or separate digital video and audio.

An inline sink port connector 1017 receives a single digital A/V streamfrom a selector 405. At any one point in time this stream may includepower, communications, and/or A/V data (it should always at least havelow-current power). The inline sink port connector 1017 passes the powerto the power circuit 1015 which distributes it to the other componentsof the digital A/V stream converter. According to an embodiment, onlythe MCU 1009 receives power when the low-current power is received.

Decoder circuitry 1001 receives the single digital A/V from theconnector 1017 and outputs a digital data bus which represents videodata of different formats (SDTV, HDTV, NTCS, PAL, etc) and color space(RGB, YCrCb, etc) and audio digital serial data is in the form 12S orSPDIF. The decoder 1001 also extracts embedded timing information intooutput signals. In an embodiment, the input stream into this block isthe HDMI data bus in the form of a TMDS bus. The converted digital videosignals are transmitted to either the optional video data mappingcircuit 1003 or to the encoder 1011 depending upon the configuration ofthe inline converter. The audio signals are transmitted to audio encoder1017. Control signals to the video decoder 1001, from the MCU 1009 arein the form I2C or SPI and may include reset, interrupts, and select(s).An exemplary circuit that may be utilized as the decode 1001 includesSilicon Graphics' Sil9031.

In an embodiment, the conversion circuitry includes a video data mappingcircuit 1003 that is an active switch that arranges the bit orderingfrom the digital bus output of the video decoder 1001 into the properformat for the encoder circuits 1011. This ordering is performed tosatisfy specific requirements of different video formats andresolutions. The re-ordering may only apply to a group of bits or theentire bus of bits transmitted from the video decoder 503 to the videodata mapping circuit 1003. Any active analog switch, such as the On SemiMC14016 or equivalent, is suitable for the application. The controlsignals provided to the video data mapping circuit 1003 depend on thespecific implementation of the analog switch and could range fromdiscrete signals to a serial bus in the form of I2C or SPI.

Video encoder circuitry 1011 is a specialized device that converts thevideo digital data into analog data of various standards (RGB, SCART,Composite, Component, S-Video, etc). exemplary circuit that may beutilized as the video encoder 1011, but not limited to, are: AnalogDevices AD7321, or equivalent. Input data into video encoder 1011 is adigital data bus from decoder 1001 and optional video data mapping 1003.Output data from encoder 1011 includes a number of dedicated analogoutputs to support the various analog standards outlined above ordigital output(s). Control signals to the encoder 1001, from the MCU1009, are in the form I2C or SPI and may include reset, interrupts, andselect(s). The video connector(s) 1013_1 serve as a port or ports forthe video output and may be specific to a particular type of output.

The microcontroller or processor (MCU) 1009 is a general purposecontroller that performs one or more of the following functions:configures the other circuits; maintains validation of communicationsover a reserved pin or pins of the cable carrying the single digital A/Vstream from the selector; software upgrades; monitor conversionactivities being performed; inspect signals; serially communicates witha connected device, etc. The MCU 1009 provides and receives numerouscontrol signals to the other circuits. For example, the MCU 1009receives interrupts from the audio/video decoder 1001. Exemplarycircuits that may be utilized as the MCU 1009 include, but not limitedto, are Atmel's AT91SAM7S, Microchip's PIC18F8722, and OKI's ML67Q4061.

The audio encoder circuitry 1017 converts the digital serial data fromdecoder 1001 to another format. Input data from video encoder 1001 is inthe form of I2S which includes serial data, clock, and left/rightchannel select. If the output is to be analog, it coverts this data intoanalog left and right channels. Exemplary circuits to perform thisinclude, but not limited to, Asahi Kasei' AK4386. If the output is to bedigital, the audio encoder 1017 may be an optical TOSLINK (or similar)transmitter that converts digital SPIDIF into an optical link. The audioconnector(s) 1013_2 serve as a port or ports for the audio output andmay be specific to a particular type of output.

FIG. 11 is an embodiment of a method of providing and maintaining powerfrom a selector to a digital A/V stream converter. Devices that arecoupled to the selector's 405 source connector port 607 are initiallysupplied with a low-current reference voltage. For example, if HDMI isused an approximately 50 mA and +5V reference is provided on the HDMIcable from the selector 405 to the digital A/V converter 407. This isthe standard current and voltage applied to that in by an HDMI sourceport.

Communication with the digital A/V stream converter 407 and the selector405 should be established after the digital A/V stream converter 407 hasreceived this low-current reference. In an embodiment, the digital A/Vstream converter 407 transmits a presence message to the selector 405(the MCU 1009 has been enabled and produces this message). If using TypeA HDMI, this message is sent on HDMI pin 14.

If a message has not been received by the selector 405 at 1101, itsimply continues to wait for a message. If a message is received at1101, the selector 405 provides the appropriate power pins of the sourceconnector 607 with a high-current reference voltage. According to anembodiment, the high-current is at least 500 mA and the voltage is +5V.This high-current reference voltage allows the remainder of theconversion circuitry of the digital A/V stream converter 407 to beactivated.

Because the digital A/V stream converter 407 may be removed or stopfunctioning at a later point in time, periodic presence checks areperformed. The selector 405 transmits a presence check message to thedigital A/V stream converter 407 at 1105 and waits for a responsemessage. If the selector 405 does not receive a response message at1107, one of two actions may be taken depending upon the configurationof the selector 405. Another presence check message may be transmittedat 1105 or the high-current voltage may be removed and replaced with alow-current reference voltage at 1109. Of course it does not matter whoinitiates the presence check and who sends the corresponding responsemessage.

FIG. 12 is an embodiment of a method of a digital A/V stream converterreceiving and maintaining power from a selector. The digital A/V streamconverter 407 receives a low-current reference voltage over a power pinat power circuit 1019 at 1201. If HDMI is being utilized the current isapproximately 50 mA and voltage +5V and power pin 18 would be used toreceive the current and voltage.

This low-current voltage allows the digital A/V stream converter 407 toturn on at least a portion of its MCU 1009 at 1203 such that the digitalA/V stream converter 407 may generate and/or respond to presencemessages. Communication with the selector 405 is established at 1205. Asdescribed earlier, the digital A/V stream converter 407 may send amessage and if found valid by the selector 405 then communication hasbeen established. Or, the selector 405 may transmit a presence messageand the digital A/V stream converter 407 may respond therebyestablishing communication.

Once communication has been established, the digital A/V streamconverter 407 enables the remainder of its conversion circuitry at 1209.

Periodically, the selector 405 and the digital A/V stream converter 407should establish communication 1211 to ensure that the digital A/Vstream converter 407 is still present and requires the higher-current.Numerous communications establishment techniques have already beendescribed.

HDMI Connection to Switch

One of the disadvantages to traditional HDMI switching is that bothconnectors of a conventional HDMI cable are identical. FIG. 13illustrates an embodiment of an extended HDMI interface. In addition tothe normal HDMI end 1307, a key 1305 is embedded in the shield of thecable end. This key 1307 extends from the shield and can be in anyorientation so long as the input and output ends of the HDMI cable havetheir respective keys in different orientations. Of course, while anHDMI cable is illustrated, any other cable/key combination may be used.

In an embodiment, the key is a clear or lightly colored material thatallows light to pass through it. For example, an internal key may shinegreen or solid when connected while an external key may shine red orflash, thus allowing a user to easily distinguish between the two. Thisalso solves the problem of a user not knowing if an issue (such as apoor or no display on a TV) is due to the components or the cableconnecting the components. As illustrated, an input end 1303 has adifferent orientation for the key than the output end 1301, thuseliminating the possibility that output of a cable could be placed intoan input port.

FIG. 14 illustrates an embodiment of the external connections of an HDMIswitch that utilizes an extended HDMI interface. The HDMI switch 1401includes multiple HDMI inputs 1405 and one HDMI output 1407. Of course,any HDMI cable may be used with any of these inputs including theconversion cable described earlier. Of course, if the conversion cableis used, the HDMI switch 1401 should employ a power distributionmechanism such as was previously described.

Additionally, an input for a key per HDMI input 1403 or output 1409 isprovided. This key input ensures that the proper cable end is used. Inan embodiment, the HDMI switch 1401 includes LEDs (or some other sort oflight source) to shine through the key when a connection has beenestablished. Like the prior art HDMI switches, this switch 1401 requiresexternal power through a port 1411.

In an embodiment, the insertion of a key into a key input of a selectoris used to determine that a converter that needs high-current power fromthe selector is coupled to the selector. The insertion of a key maytrigger as a switch or hall-effect sensor inside the selector thatvalidates such a converter is present. This technique may be is inconjunction with or instead of the communication schemes describedearlier.

Closing Comments

Processes taught by the discussion above may be performed with programcode such as machine-executable instructions that cause a machine thatexecutes these instructions to perform certain functions. In thiscontext, a “machine” may be a machine that converts intermediate form(or “abstract”) instructions into processor specific instructions (e.g.,an abstract execution environment such as a “virtual machine” (e.g., aJava Virtual Machine), an interpreter, a Common Language Runtime, ahigh-level language virtual machine, etc.)), and/or, electroniccircuitry disposed on a semiconductor chip (e.g., “logic circuitry”implemented with transistors) designed to execute instructions such as ageneral-purpose processor and/or a special-purpose processor. Processestaught by the discussion above may also be performed by (in thealternative to a machine or in combination with a machine) electroniccircuitry designed to perform the processes (or a portion thereof)without the execution of program code.

It is believed that processes taught by the discussion above may also bedescribed in source level program code in various object-orientated ornon-object-orientated computer programming languages (e.g., Java, C#,VB, Python, C, C++, J#, APL, Cobol, Fortran, Pascal, Perl, etc.)supported by various software development frameworks (e.g., MicrosoftCorporation's.NET, Mono, Java, Oracle Corporation's Fusion etc.). Thesource level program code may be converted into an intermediate form ofprogram code (such as Java byte code, Microsoft Intermediate Language,etc.) that is understandable to an abstract execution environment (e.g.,a Java Virtual Machine, a Common Language Runtime, a high-level languagevirtual machine, an interpreter, etc.).

According to various approaches the abstract execution environment mayconvert the intermediate form program code into processor specific codeby, 1) compiling the intermediate form program code (e.g., at run-time(e.g., a JIT compiler)), 2) interpreting the intermediate form programcode, or 3) a combination of compiling the intermediate form programcode at run-time and interpreting the intermediate form program code.Abstract execution environments may run on various operating systems(such as UNIX, LINUX, Microsoft operating systems including the Windowsfamily, Apple Computers operating systems including MacOS X,Sun/Solaris, OS/2, Novell, etc.).

An article of manufacture may be used to store program code. An articleof manufacture that stores program code may be embodied as, but is notlimited to, one or more memories (e.g., one or more flash memories,random access memories (static, dynamic or other)), optical disks,CD-ROMs, DVD ROMs, EPROMs, EEPROMs, magnetic or optical cards or othertype of machine-readable media suitable for storing electronicinstructions. Program code may also be downloaded from a remote computer(e.g., a server) to a requesting computer (e.g., a client) by way ofdata signals embodied in a propagation medium (e.g., via a communicationlink (e.g., a network connection)).

FIG. 15 shows an embodiment of a computing system (e.g., a computer).The exemplary computing system of FIG. 15 includes: 1) one or moreprocessors 1501; 2) a memory control hub (MCH) 1502; 3) a system memory1503 (of which different types exist such as DDR RAM, EDO RAM, etc,); 4)a cache 1504; 5) an I/O control hub (ICH) 1505; 6) a graphics processor1506; 7) a display/screen 1507 (of which different types exist such asCathode Ray Tube (CRT), Thin Film Transistor (TFT), Liquid CrystalDisplay (LCD), DPL, etc.; 15) one or more I/O devices 1508.

The one or more processors 1501 execute instructions in order to performwhatever software routines the computing system implements. Theinstructions frequently involve some sort of operation performed upondata. Both data and instructions are stored in system memory 1503 andcache 1504. Cache 1504 is typically designed to have shorter latencytimes than system memory 1503. For example, cache 1504 might beintegrated onto the same silicon chip(s) as the processor(s) and/orconstructed with faster SRAM cells whilst system memory 1503 might beconstructed with slower DRAM cells. By tending to store more frequentlyused instructions and data in the cache 1504 as opposed to the systemmemory 1503, the overall performance efficiency of the computing systemimproves.

System memory 1503 is deliberately made available to other componentswithin the computing system. For example, the data received from variousinterfaces to the computing system (e.g., keyboard and mouse, printerport, LAN port, modem port, etc.) or retrieved from an internal storageelement of the computing system (e.g., hard disk drive) are oftentemporarily queued into system memory 1503 prior to their being operatedupon by the one or more processor(s) 1501 in the implementation of asoftware program. Similarly, data that a software program determinesshould be sent from the computing system to an outside entity throughone of the computing system interfaces, or stored into an internalstorage element, is often temporarily queued in system memory 1503 priorto its being transmitted or stored.

The ICH 1505 is responsible for ensuring that such data is properlypassed between the system memory 1503 and its appropriate correspondingcomputing system interface (and internal storage device if the computingsystem is so designed). The MCH 1502 is responsible for managing thevarious contending requests for system memory 1503 access amongst theprocessor(s) 1501, interfaces and internal storage elements that mayproximately arise in time with respect to one another.

One or more I/O devices 1508 are also implemented in a typical computingsystem. I/O devices generally are responsible for transferring data toand/or from the computing system (e.g., a networking adapter); or, forlarge scale non-volatile storage within the computing system (e.g., harddisk drive). ICH 1505 has bi-directional point-to-point links betweenitself and the observed I/O devices 1508.

In the foregoing specification, the invention has been described withreference to specific exemplary embodiments thereof. It will, however,be evident that various modifications and changes may be made theretowithout departing from the broader spirit and scope of the invention asset forth in the appended claims. For example, it should be understoodthat one or more of the circuits of the selector or inline convertersmay be combined or the functionality provided by a single circuitdivided up among multiple circuits. Alternative embodiments of aconverter and selector may be used so long as power may be supplied fromone component to another over existing power pins. Other devices otherthan a selector may also be used to provide power and communication witha converter. For example, if an HDTV were to have similar powermonitoring and communications capabilities it too could power thecircuitry of a connector. Additionally, while many of the describedembodiments discussed the use of the HDMI format, the techniques ofinline signal conversion and power supply over a cable to inline signalconversion circuitry will be applicable to future digital and analogformats including the conversion of HDMI into a another single A/Vstream format. It should be noted that HDMI cables that allowbi-directional communication and power throughput are not compliant withthe current HDMI standards.

1. A method comprising: determining if a reference voltage associatedwith a converter is present on a power pin; and providing a low-currentreference voltage to the converter over a cable if there is not areference voltage present on the power pin.
 2. The method of claim 1,further comprising: attempting to establish communications with theconverter over a reserved pin; removing the low-current referencevoltage if communications cannot be established; and providing ahigh-current reference voltage if communications are established.
 3. Themethod of claim 1, wherein attempting to establish communications withthe converter comprises: receiving a message from the converter; anddetermining if the message is a valid presence message.
 4. The method ofclaim 2, wherein the reserved pin is pin 14 of an HDMI connector.
 5. Themethod of claim 2, further comprising: transmitting a presence checkmessage to the converter; and removing the high-current referencevoltage if a response to the transmitted presence check message is notreceived.
 6. The method of claim 1, wherein the power pin is pin 18 ofan HDMI connector.
 7. A method comprising: receiving a low-currentvoltage over an existing power pin from a high-current voltage supplyingdevice; establishing communications with the high-current voltagesupplying device; receiving a high-current voltage over the existingpower pin; and providing power to conversion circuitry using thehigh-current voltage received.
 8. The method of claim 7, whereinestablishing communications with a high-current voltage supplying devicecomprises: transmitting a presence message.
 9. The method of claim 7,wherein the high-current is approximately 500 mA and the voltage is +5V.10. The method of claim 7, wherein the low-current is approximately 50mA and the voltage is +5V.
 11. An inline converter comprising: a videodecoder to convert an analog or digital video of a different format andstandard into digital video signals; an audio receiver to convert audiosignals from one format to a digital audio stream; an encoder to encodethe digital video signals and digital audio stream into a single digitalA/V stream; a microcontroller to control the operation of the videodecoder, audio receiver, and encoder; and a power circuit to providepower to the video decoder, audio receiver, microcontroller, andencoder, wherein the power circuit receives its power from anotherdevice over an existing power pin.
 12. The inline converter of claim 11,wherein the single digital A/V stream is an HDMI stream.
 13. The inlineconverter of claim 11, further comprising: a video data mapping circuitactive switch to arrange the output of the video decoder into a properformat for the encoder circuit.
 14. The inline converter of claim 11,wherein the analog video is one of composite, component, S-video, andVGA.
 15. The inline converter of claim 11, wherein the digital video isDVI.
 16. An apparatus comprising: N sink ports to receive N singledigital A/V streams; a N×M switch to select between the N single digitalA/V streams and select M single digital A/V stream outputs; amicrocontroller to control the N×M switch and communicate with anexternal device; and a power circuit to supply power to the externaldevice.
 17. The apparatus of claim 16, wherein the single digital A/Vstreams are HDMI.
 18. The apparatus of claim 17, the microcontroller tocommunicate with the external device over sink port pin 14 and the powercircuit to provide power over sink port pin
 18. 19. A method comprising:providing a digital A/V stream converter with a low-current referencevoltage; establishing communications with the digital A/V streamconverter; providing the digital A/V stream converter with ahigh-current reference voltage over a cable after communications havebeen established.
 20. The method of claim 19, further comprising:re-establishing communications with the digital A/V stream converterperiodically.
 21. The method of claim 19, further comprising: removingthe a high-current reference voltage over a cable communications cannotbe re-established; and providing the digital A/V stream converter with alow-current reference voltage over a cable if communications cannot bere-established
 22. A method comprising: receiving low-current voltagefrom a selector over an existing power pin; turning on a portion of anmicrocontroller using the low-current voltage; establishingcommunication with the selector using the microcontroller; and receivinghigh-current voltage from the selector over the existing power pin; andturning on conversion circuits using the high-current voltage.
 23. Themethod of claim 22, wherein the existing power pin is HDMI pin
 18. 24.The method of claim 22, wherein communication is established over HDMIpin
 14. 25. The method of claim 24, wherein the high-current isapproximately 500 mA and the voltage is +5V.
 26. An apparatuscomprising: a audio/video decoder to convert a digital A/V stream into adigital stream of a different format and standard into digital videosignals; an encoder to encode the digital video signals into separatedigital or analog video and audio streams; a microcontroller to controlthe operation of the audio/video decoder and encoder; and power circuitprovide power to the video decoder, microcontroller, and encoder,wherein the power circuit receives its power from another device over anexisting power pin.